An electrochemical test sensor for detecting the analyte concentration of a fluid test sample includes a base, a dielectric layer, a reagent layer, a light guide area, and a lid. The base provides a flow path for the test sample having on its surface a counter electrode and a working electrode adapted to electrically communicate with a detector of electrical current. The dielectric layer forms a dielectric window therethrough. The reagent layer includes an enzyme that is adapted to react with the analyte. The lid is adapted to mate with the base and to assist in forming a capillary space with an opening for the introduction of the test sample thereto. The light guide area transmits light towards the capillary space.